diff --git a/.github/workflows/ci_workflows.yml b/.github/workflows/ci_workflows.yml
index 9d1d04c42..44c191816 100644
--- a/.github/workflows/ci_workflows.yml
+++ b/.github/workflows/ci_workflows.yml
@@ -30,7 +30,7 @@ jobs:
         - linux: py39-test
         - linux: py310-test-all
         - linux: py311-test
-        - linux: py311-test-all
+        - linux: py312-test-all
 
         # Documentation build
         - linux: py38-docs
@@ -43,14 +43,21 @@ jobs:
         - macos: py39-test
         - macos: py310-test-all
         - macos: py311-test
+        - macos: py312-test-all
 
         # Test some configurations on Windows
         - windows: py38-test
-        - windows: py310-test
+        - windows: py39-test
 
         # Test against latest developer versions of some packages
         - linux: py310-test-dev-all
         - linux: py311-test-dev
+        - linux: py312-test-dev-all
+
+        - macos: py311-test-dev-all
+        - macos: py312-test-dev
+
+        - windows: py310-test-dev
 
   publish:
     needs: tests
diff --git a/glue/utils/array.py b/glue/utils/array.py
index 9213e993f..7da7baaa3 100644
--- a/glue/utils/array.py
+++ b/glue/utils/array.py
@@ -504,6 +504,8 @@ class categorical_ndarray(np.ndarray):
 
     def __new__(cls, value, dtype=None, copy=True, order=None, subok=False,
                 ndmin=0, categories=None):
+        if not copy and np.lib.NumpyVersion(np.__version__) >= "2.0.0rc1":
+            copy = None
         result = np.array(value, dtype=dtype, copy=copy, order=order,
                           subok=True, ndmin=ndmin).view(categorical_ndarray)
         if categories is not None:
diff --git a/setup.cfg b/setup.cfg
index 44e4f5bed..479fe963a 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -28,6 +28,7 @@ install_requires =
     pandas>=1.2
     echo>=0.6
     astropy>=4.0
+    fast_histogram>=0.12
     setuptools>=30.3.0
     ipython>=4.0
     dill>=0.2
diff --git a/tox.ini b/tox.ini
index 469416cda..16da8489c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{38,39,310,311}-{codestyle,test,docs}-all-{dev,legacy}{,-visual}
+    py{38,39,310,311,312}-{codestyle,test,docs}-all-{dev,legacy}{,-visual}
 requires = pip >= 18.0
            setuptools >= 30.3.0
 
@@ -10,7 +10,7 @@ passenv =
     DISPLAY
     HOME
 setenv =
-    dev: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+    dev: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/liberfa/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
     visual: MPLFLAGS = -m "mpl_image_compare" --mpl --mpl-generate-summary=html --mpl-results-path={toxinidir}/results --mpl-hash-library={toxinidir}/glue/tests/visual/{envname}.json --mpl-baseline-path=https://raw.githubusercontent.com/glue-viz/glue-core-visual-tests/images/{envname}/
 whitelist_externals =
     find
@@ -22,7 +22,9 @@ changedir =
     docs: doc
 deps =
     dev: numpy>=0.0.dev0
+    dev: scipy>=0.0.dev0
     dev: astropy>=0.0.dev0
+    # LTS
     lts: astropy==5.0.*
     lts: matplotlib==3.5.*
     # Pin numpy-lts until permanent solution for #2353/#2428
@@ -46,6 +48,12 @@ extras =
     all: all
     docs: docs
     visual: visualtest
+# Need `--pre` for packages like pandas having no released version supporting numpy>=2.0 yet,
+# + `--no-deps` for casa-formats-io having no branch for numpy>=2.0 -
+# for as long all test deps need to be manually pulled in above as well!
+install_command =
+    !dev: python -I -m pip install
+    dev: python -I -m pip install -v
 commands =
     test: pip freeze
     test: pytest --pyargs glue --cov glue --cov-config={toxinidir}/setup.cfg {env:MPLFLAGS} {posargs}